Making Realgar Orange Pigment — The Arsenic Companion to Orpiment
Realgar (α-As₄S₄, also written As₂S₂ or AsS) is a vivid orange-red arsenic sulfide mineral that has been used as a pigment since antiquity. It is the chemical sibling of orpiment (As₂S₃) — where orpiment is golden-yellow, realgar is orange-red. Both minerals often occur together in volcanic deposits and hot spring environments. Ancient Egyptian, Chinese, and Roman artists used realgar for its brilliant orange colour, which no other ancient pigment could match.
Realgar has a unique instability: exposure to prolonged light causes it to convert to pararealgar (β-As₄S₄), a powdery yellow form. This photodegradation means realgar paintings that were once vivid orange may now appear faded and yellowish — a process that has been observed in medieval manuscripts and Chinese paintings.
SAFETY WARNING: Realgar is an ARSENIC COMPOUND and is HIGHLY TOXIC. Arsenic is a cumulative poison causing damage to the nervous system, liver, kidneys, and skin. ALL handling must be done with full respiratory protection (P100 respirator), chemical-resistant gloves, and eye protection. ALWAYS grind WET — never dry-grind realgar, as dry grinding produces respirable arsenic-containing dust. Work in a well-ventilated area. Realgar is INCOMPATIBLE with copper-based and lead-based pigments — direct contact causes chemical reactions that darken both pigments.
ខ្លឹមសារគ្រោះថ្នាក់
ប្លង់នេះមាននីតិវិធីគ្រោះថ្នាក់។ សូមចូលប្រើ និងបើកមាតិកាគ្រោះថ្នាក់នៅក្នុងការកំណត់គណនីរបស់អ្នកដើម្បីមើលការណែនាំជាជំហាន។
ប្លង់ពាក់ព័ន្ធ
ប្លង់ទាំងនេះចែករំលែកចំណេះដឹង — បច្ចេកទេស សម្ភារៈ ឬគោលការណ៍
Making Cinnabar Red Pigment — Grinding Mercury Sulfide into the Most Vivid Red of the Ancient World
ដោយ Charlie
សិល្បៈ
Making Naples Yellow (Lead Antimonate) — The Oldest Known Synthetic Yellow Pigment
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សិល្បៈ
Making Egg Tempera Paint — The Medieval Panel Painting Medium
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Making Oil Paint from Raw Pigments — Grinding Pigments in Linseed Oil
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Making Watercolour Paint from Raw Pigments — Gum Arabic Binder
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សិល្បៈ
Making Lead White (Flake White) — The Dutch Stack Process for the Most Important Pigment in Oil Painting History
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សិល្បៈ
Making Malachite Green Pigment — Grinding the Copper Mineral into Painter's Green
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Making Gamboge Yellow — Preparing the Tree Resin Pigment of Southeast Asian Painters
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Making Red Ochre by Calcining Yellow Ochre — The Oldest Deliberate Pigment Transformation
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សិល្បៈ
Making Yellow Ochre Pigment — Grinding and Levigating Goethite into the Oldest Painter's Yellow
ដោយ Charlie
សិល្បៈ
CC0 សាធារណៈ
ប្លង់នេះត្រូវបានចេញផ្សាយក្រោម CC0។ អ្នកមានសិទ្ធិចម្លង កែប្រែ ចែកចាយ និងប្រើប្រាស់ដោយមិនចាំបាច់សុំអនុញ្ញាត។
គាំទ្រអ្នកបង្កើតដោយទិញផលិតផលតាមរយៈប្លង់របស់ពួកគេ ដែលពួកគេទទួលបាន កម្រៃជើងសារអ្នកបង្កើត កំណត់ដោយអ្នកលក់ ឬបង្កើតកំណែថ្មីនៃប្លង់នេះ ហើយបញ្ចូលជាការតភ្ជាប់ក្នុងប្លង់របស់អ្នកដើម្បីចែករំលែកចំណូល។